Limits to Human Population Growth (DP IB Environmental Systems & Societies (ESS))

Limits to Human Population Growth

• The degradation of the environment and the consumption of finite resources have significant implications for human population growth

  • These factors are expected to limit population growth and these unsustainable practices can lead to human populations exceeding their carrying capacity, which can eventually lead to the collapse of these populations

Environmental Degradation as a Limiting Factor

• Human populations rely on the natural environment for resources such as food, water, energy, and materials

• However, the degradation of ecosystems, including deforestation, soil erosion, pollution, and loss of biodiversity, decreases the capacity of the environment to support growing populations

• For example:

  • Deforestation reduces the availability of forests for timber, biodiversity conservation, and carbon sequestration - this loss of ecosystem services can lead to reduced agricultural productivity, increased vulnerability to natural disasters, and decreased availability of clean water, all of which can limit human population growth

  • Pollution, such as air and water pollution, can have detrimental effects on ecosystems and human health, compromising the overall well-being and resilience of human populations - pollution from human activities can lead to the degradation of ecosystems, decline in biodiversity, and contamination of essential resources like drinking water

Finite resources as a Limiting Factor

• Human populations rely on finite resources, including fossil fuels, minerals, and fresh water

• These resources have limited availability, and their extraction and consumption rates can outpace their natural replenishment

• For example:

  • Depletion of fossil fuels, such as coal, oil, and natural gas, not only contributes to climate change but also poses challenges for energy production and transportation systems - as these resources become scarcer, their extraction becomes more challenging and expensive, hindering economic growth and development

  • Overexploitation of freshwater resources can lead to water scarcity, affecting agricultural productivity, human health, and overall societal wellbeing - this is particularly crucial in regions already facing water stress or located in arid and semi-arid climates.

Unsustainable Practices and Exceeding Carrying Capacity

Photo by Eelco Böhtlingk on Unsplash 

As we deplete our finite resources, we are decreasing the carrying capacity of the planet to sustain the current global population - as the more readily available stocks of resources such as fossil fuels are used up, their extraction becomes increasingly difficult and expensive, which is one of the reasons human populations need to focus on reducing their fossil fuel dependence as quickly as possible

• If human populations continue to deplete resources and degrade the environment at an unsustainable rate, they risk surpassing the carrying capacity of their ecosystems

• When carrying capacity is exceeded:

  • Resource scarcity intensifies, leading to food shortages, water scarcity, and energy crises - this can trigger social unrest, conflicts, and migrations as populations struggle to meet their basic needs

  • Ecosystems can start to collapse, resulting in a loss of biodiversity, disruption of essential ecosystem services, and increased vulnerability to environmental disturbances - this can have cascading effects on human well-being and livelihoods

Case Study: Easter Island

Photo by Thomas Griggs on Unsplash 

Although Rapa Nui (Easter Island) is most famous for its moai, also known as the Easter Island Heads, this island also demonstrates how a human population can collapse if unsustainable resource use causes the population to exceed its carrying capacity

• Easter Island (also known as Rapa Nui), located in the southeastern Pacific Ocean, provides a notable case study where the degradation of the environment and the consumption of finite resources have significantly limited human population growth

  • The island's history provides a clear warning of the consequences of unsustainable practices

• In the past, Easter Island was a thriving Polynesian society with abundant natural resources, including lush forests

  • The inhabitants of Easter Island relied heavily on the island's forests for various needs, such as timber for construction, wood fuel, and agriculture

• Due to overexploitation of timber resources, the island's forests were depleted, leading to significant deforestation

  • The loss of trees resulted in soil erosion, reduced agricultural productivity, and limited availability of other essential resources

• The degradation of the environment and the depletion of finite resources significantly decreased the island's carrying capacity

  • The human population on Easter Island was no longer sustainable, and as a result, it declined dramatically

• The decline in food production, scarcity of construction materials, and deteriorating living conditions contributed to societal challenges

  • Historical evidence suggests that the collapse of the society on Easter Island led to social upheaval, conflict, and even cannibalism may have occurred as resources became scarce

• The case of Easter Island clearly demonstrates the consequences of unsustainable practices, emphasising the importance of responsible resource management and sustainable approaches to ensure long-term human well-being and environmental preservation